Explosive cartridge



2 Sheets-Sheet 1 Filed Feb. 25, 1956 May 26, 1959 H. MAGER EXPLOSIVE CARTRIDGE Filed Feb. 25, 1956 2 Sheets-Sheet 2 INVENTOR ATTOR N EY United States Patent Mining or blasting cartridges having an aluminium or aluminium alloy case are well known in the art.

My invention has for its object a cartridge of this type, the case of which takes an active part in the explosion and increases substantially its efiiciency considered as a practical utilisation coeflicient.

According to my invention, the ratio between the thickness of the wall of the aluminium or aluminium alloy case and the diameter of the cartridge constituted by the powder core ranges between about 1:80 and 1:1000.

Experiments have shown that if such ratios are respected, the case takes an active part in the explosion of the powder mixture contained in it.

It is possible to establish a stack of seismic cartridges according to my invention through superposition of the cartridges with an interengagement of annular ribs and grooves formed in the depressed cover of one cartridge slightly above the bottom of said cover which is fluidtight- 1y fitted in its case throughout the height of this peripheral wall.

Each cover may furthermore be provided along the outer surface of its main transverse section with a depression inside which an electric detonator is housed. It is also provided in registry with said depression with a longitudinal groove or recess housing the wires feeding the detonator and connected with an external supply of energy.

The different above disclosed features of my invention together with other features will appear clearly in the reading of the following description, reference being made to the accompanying diagrammatic drawings illustrating by way of example and by no means in a binding sense a preferred embodiment of my improved cartridge. In said drawings:

Fig. 1 is a half-sectional view thereof.

Fig. 2 is a plan view from above.

Fig. 3 is a vertical sectional view through line III-III of Fig. 2, the case being shown before it is closed.

Fig. 4 is an elevational view of a stack constituted by three of such cartridges.

Fig. 5 is a vertical sectional view of said stack on an enlarged scale.

The case of the cartridge according to my invention is constituted chiefly by a tubular sheath 1 having preferably a circular cross-section. Said sheath 1 is made advantageously of a sheet of aluminium, zinc, copper or of an alloy of such metals and its thickness is such that, taking into account the diameter of the sheath, the case may take part also in the explosion of the blasting charge inside it. Thus, for instance in the case of a sheath the diameter of which ranges between 25 and 50 millimeters, the metal sheet which forms it may be a sheet of aluminium the thickness of which ranges between 0.05 and 0.3 millimeters while its resistance to breaking is above 3 kg./sq. crn.

Said sheath 1 which is pemianently closed at one of its ends 3 is advantageously obtained through flowing of the originally selected metal sheet.

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In the proximity with its bottom 3, the sheath 1 is provided in the outer surface of its wall first with a peripheral groove 4 and above the latter with a peripheral outwardly projecting rib 5.

The upper end of the sheath 1 is open and its wall flares outwardly at 6 as illustrated in the drawings so as to allow the fitting there of a dished closing cover 7. The latter includes a bottom 3 and a skirt or upstanding peripheral section 9 the upper edge of which is folded and crimped over the upper edge of the sheath 1 so as to provide for a fluidtight closing of the case. The cover 7 is provided furthermore with an inwardly directed rib 10 in its skirt section.

The different elements including the groove 4 and the rib 5 on the sheath 1 and the rib 10 on the cover 7 are designed and located in a manner such that, through a fitting of the lower end of a sheath 1 inside the cover 7 of an adjacent cartridge, the rib 10 in the cover of the latter engages the groove 4 in the first sheath while the upper edge of the cover 7 of the second cartridge abuts against the outwardly directed rib 5 of the first sheath,

I obtain thus an instantaneous interengagement betweenv the two cases together with a limitation of the engagement of one case inside the other.

It is thus possible to insert in succession a number of cases inside one another so as to obtain a stack of cartridges making up the desired length. This alignment of cases is obtained instantaneously and reliably and without any risk by reason of the speed with which one case may be inserted inside another and also of the abutment produced by the rib 5 on each case against the upper edge of the cover of the next casewherethrough the depth of interengagement between successive cases is limited.

Furthermore, by reason of the small bearing surface between two adjacent cases and of the clearance between the rib 10 of one cover and the inside of the groove 4 in the sheath of the cooperating case, I obtain a stack in which the cartridges are not aligned rigidly in end to end relationship.

This leads to the possibility for said stack to be deformed when it engages the blasting hole in accordance with the outline of the latter, which outline is never perfectly rectilinear.

In order to prevent furthermore the stack of cartridges from rising when it has been introduced inside a blasting hole partly filled with water for instance, it is of advantage according to my invention to fit inside the cover of the uppermost cartridge a ring which may be provided with an upper toothed edge adapted to bite into the side wall of the blasting hole as soon as a slight slope is given to the stack of cartridges which is thus prevented from rising out of the blasting hole.

It should be remarked that the bottom 8 of the cover 7 of each sheath 1 is provided with a diametrical or transverse recess 14 adapted to carry if desired a detonator 15 as shown in Fig. 5, said detonator being secured to the Wall of said recess through gluing for instance. In order to feed current through the electric Wire 16 to the detonator in said recess, a groove 17 is formed longitudinally in the skirt 9 of the cover in register with said recess while a corresponding groove 18 is formed in the flaring end 6 of the sheath 1 to house said groove 17 in the cover, the two grooves 17 and 18 registering when the cover 7 is fitted inside the sheath 1.

In order to reinforce the deflagration, it is possible to provide as illustrated in Fig. 5 two relays 19 to either side of the detonator 15.

What I claim is:

l. A stack of superposed similar mining cartridges each of which comprises a thin elongated case, including a cylindrical wall made of a rigid sheet of metal containing aluminium as a predominant component, the thickness of which sheet ranges between about 0.05 and 0.3 mm. and the breaking resistance of which sheet is equal to about 3 kgs. per sq. cm., a bottom closing one end of the cylindrical well, an outwardly projecting annularrib rigid with the cylindrical wall near the'bottom closing the latter and "a cylindrical core of an explosive powder constituted mainly by inorganic nitrates, filling the case throughout'the major part of its height, and a dished cover including a transverse solid main section covering the core in the case and provided with a substantially radial recess and a short upstanding annular lateral wall fitted inside the upper end of the case and provided with an annular rib -for yielding engagement with the annular rib in theadjacent end of the cartridge case, and a detonator housed insidetherecess in the main section of the cover.

2. A stack of superposed similar mining cartridges,

each of which comprises a thin cylindrical case including a cylindrical wall made of a rigid-sheet of metal containing aluminium as a predominant component, the thickness of which sheet ranges between about 0.05 and 0.3 mm. and the breaking resistance of which sheet is equal to about 3 kgs. per sq. cm., a bottom closing one end of the cylindrical wall, an outwardly projecting annular rib rigid with the cylindrical wall near the bottom closing the latterand *a cylindrical core of an explosive powder con- 4 stituted mainly by inorganic nitrates filling the case throughout the major part of its height and a dished cover including a transverse solid main section covering the core in the case and provided with a substantially radial recess and an upstanding annular lateral wall fitted inside the upper end of the case and provided with an annular rib for yielding engagement with the annular rib in the adjacent end of the cartridge case and provided further with an inwardly facing vertical groove registering with the recess in the bottom section of the cover and a detonator housed inside the recess in the main section of the core and a wire connecting said detonator and passing through'the groove in the upstanding lateral wall.

References Cited in the file of this patent UNITED STATES PATENTS 2,052,475 Jones et a1 Aug. 25, 1936 2,061,558 Brandt Nov. 24, 1936 2,238,939 Lewiset al. Apr. 22, 1941 2,345,887 Rothrock Apr. 4, 1944 2,358,795 Djidics et al. "Sept. 26, 1944 FOREIGN PATENTS 704,125 Great Britain Feb. 24, 1954 

1. A STACK OF SUPERPOSED SIMILAR MINING CARTRIDGES EACH OF WHICH COMPRISES A THIN ELONGATED CASE, INCLUDING A CYLINDRICAL WALL MADE OF A RIGID SHEET OF METAL CONTAINING ALUMINIUM AS A PREDOMINANT COMPONENT, THE THICKNESS OF WHICH SHEET RANGES BETWEEN ABOUT 0.05 AND 0.3 MM. AND THE BREAKING RESISTANCE OF WHICH SHEET IS EQUAL TO ABOUT 3 KGS. PER SQ.CM., A BOTTOM CLOSING ONE END OF THE CYLINDRICAL WALL, AND OUTWARDLY PROJECTING ANNULAR RIB RIGID WITH THE CYLINDRICAL WALL NEAR THE BOTTOM CLOSING THE LATTER AND A CYLINDRICAL CORE OF AN EXPLOSIVE POWDER CONSTITUTED MAINLY BY INORGANIC NITRATES, FILLING THE CASE THROUGHOUT THE MAJOR PART OF ITS HEIGHT, AND A DISHED COVER INCLUDING A TRANSVERSE SOLID MAIN SECTION COVERING THE CORE IN THE CASE AND PROVIDED WITH A SUBSTANTIALLY RADIAL RECESS AND A SHORT UPSTANDING ANNULAR LATERAL WALL FITTED INSIDE THE UPPER END OF THE CASE AND PROVIDED WITH AN ANNULAR RIB FOR YIELDING ENGAGEMENT WITH THE ANNULAR RIB IN THE ADJACENT END OF THE CARTRIDGE CASE, AND A DETONATOR HOUSED INSIDE THE RECESS IN THE MAIN SECTION OF THE COVER. 